//	---------------------------------------------------------------------------
//
//	@file		TwDualGLUT.c
//	@brief		This example illustrates the use of AntTweakBar with multiple
//				windows. Here we are using GLUT to create a main window having
//				two sub-windows, each sub-window has a tweak bar.
//				This example extends the TwSimpleGLUT example.
//
//				AntTweakBar: http://anttweakbar.sourceforge.net/doc
//				OpenGL:		 http://www.opengl.org
//				GLUT:		 http://opengl.org/resources/libraries/glut
//
//	---------------------------------------------------------------------------


#include <AntTweakBar.h>

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#if defined(_WIN32) || defined(_WIN64)
//	MiniGLUT.h is provided to avoid the need of having GLUT installed to
//	recompile this example. Do not use it in your own programs, better
//	install and use the actual GLUT library SDK.
#	define USE_MINI_GLUT
#endif

#if defined(USE_MINI_GLUT)
#	include "../src/MiniGLUT.h"
#elif defined(__APPLE__)
#	include <GLUT/glut.h>
#else
#	include <GL/glut.h>
#endif


// This example displays one of the following shapes in each sub-window
typedef enum { SHAPE_TEAPOT=1, SHAPE_TORUS, SHAPE_CONE } Shape;
#define NUM_SHAPES 3

typedef struct
{
	int   WinID;
	TwBar *Bar;
	Shape ObjectShape;
	float Zoom;
	float Rotation[4];
	int   AutoRotate;
	int   RotateTime;
	float RotateStart[4];
	float MatAmbient[4];
	float MatDiffuse[4];
	float LightMultiplier;
	float LightDirection[3];
} SubWindowData;

SubWindowData g_SubWindowData[2];


// Routine to set a quaternion from a rotation axis and angle
// ( input axis = float[3] angle = float  output: quat = float[4] )
void SetQuaternionFromAxisAngle(const float *axis, float angle, float *quat)
{
	float sina2, norm;
	sina2 = (float)sin(0.5f * angle);
	norm = (float)sqrt(axis[0]*axis[0] + axis[1]*axis[1] + axis[2]*axis[2]);
	quat[0] = sina2 * axis[0] / norm;
	quat[1] = sina2 * axis[1] / norm;
	quat[2] = sina2 * axis[2] / norm;
	quat[3] = (float)cos(0.5f * angle);
}


// Routine to convert a quaternion to a 4x4 matrix
// ( input: quat = float[4]  output: mat = float[4*4] )
void ConvertQuaternionToMatrix(const float *quat, float *mat)
{
	float yy2 = 2.0f * quat[1] * quat[1];
	float xy2 = 2.0f * quat[0] * quat[1];
	float xz2 = 2.0f * quat[0] * quat[2];
	float yz2 = 2.0f * quat[1] * quat[2];
	float zz2 = 2.0f * quat[2] * quat[2];
	float wz2 = 2.0f * quat[3] * quat[2];
	float wy2 = 2.0f * quat[3] * quat[1];
	float wx2 = 2.0f * quat[3] * quat[0];
	float xx2 = 2.0f * quat[0] * quat[0];
	mat[0*4+0] = - yy2 - zz2 + 1.0f;
	mat[0*4+1] = xy2 + wz2;
	mat[0*4+2] = xz2 - wy2;
	mat[0*4+3] = 0;
	mat[1*4+0] = xy2 - wz2;
	mat[1*4+1] = - xx2 - zz2 + 1.0f;
	mat[1*4+2] = yz2 + wx2;
	mat[1*4+3] = 0;
	mat[2*4+0] = xz2 + wy2;
	mat[2*4+1] = yz2 - wx2;
	mat[2*4+2] = - xx2 - yy2 + 1.0f;
	mat[2*4+3] = 0;
	mat[3*4+0] = mat[3*4+1] = mat[3*4+2] = 0;
	mat[3*4+3] = 1;
}


// Routine to multiply 2 quaternions (ie, compose rotations)
// ( input q1 = float[4] q2 = float[4]	output: qout = float[4] )
void MultiplyQuaternions(const float *q1, const float *q2, float *qout)
{
	float qr[4];
	qr[0] = q1[3]*q2[0] + q1[0]*q2[3] + q1[1]*q2[2] - q1[2]*q2[1];
	qr[1] = q1[3]*q2[1] + q1[1]*q2[3] + q1[2]*q2[0] - q1[0]*q2[2];
	qr[2] = q1[3]*q2[2] + q1[2]*q2[3] + q1[0]*q2[1] - q1[1]*q2[0];
	qr[3]  = q1[3]*q2[3] - (q1[0]*q2[0] + q1[1]*q2[1] + q1[2]*q2[2]);
	qout[0] = qr[0]; qout[1] = qr[1]; qout[2] = qr[2]; qout[3] = qr[3];
}


// Return elapsed time in milliseconds
int GetTimeMs()
{
#if !defined(_WIN32)
	return glutGet(GLUT_ELAPSED_TIME);
#else
	// glutGet(GLUT_ELAPSED_TIME) seems buggy on Windows
	return (int)GetTickCount();
#endif
}


// Find the current WindowData
SubWindowData *GetCurrentSubWindowData()
{
	int i, currWinID;
	currWinID = glutGetWindow();
	for (i = 0; i < 2; i++)
		if (g_SubWindowData[i].WinID == currWinID)
			return &g_SubWindowData[i];
	return NULL;
}


// Callback function called by GLUT to render the main window content
void DisplayMainWindow(void)
{
	// Clear frame buffer
	glClearColor(1, 0.8f, 0.4f, 1);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	// Present frame buffer
	glutSwapBuffers();
}


// Callback function called by GLUT when the main window size has changed
void ReshapeMainWindow(int width, int height)
{
	if (width > 32 && height > 32)
	{
		glutSetWindow(g_SubWindowData[0].WinID);
		glutPositionWindow(8, 8);
		glutReshapeWindow(width/2-16, height-16);

		glutSetWindow(g_SubWindowData[1].WinID);
		glutPositionWindow(width/2+8, 8);
		glutReshapeWindow(width/2-16, height-16);
	}
}


// Callback function called by GLUT to render sub-window content
void DisplaySubWindow(void)
{
	float v[4]; // will be used to set light parameters
	float mat[4*4]; // rotation matrix
	SubWindowData *win;

	win = GetCurrentSubWindowData();
	if (win == NULL) return;

	// Tell AntTweakBar which is the current window
	TwSetCurrentWindow(win->WinID);

	// Clear frame buffer
	glClearColor(0, 0, 0, 1);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

	glEnable(GL_DEPTH_TEST);
	glDisable(GL_CULL_FACE);
	glEnable(GL_NORMALIZE);

	// Set light
	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0);
	v[0] = v[1] = v[2] = win->LightMultiplier*0.4f; v[3] = 1.0f;
	glLightfv(GL_LIGHT0, GL_AMBIENT, v);
	v[0] = v[1] = v[2] = win->LightMultiplier*0.8f; v[3] = 1.0f;
	glLightfv(GL_LIGHT0, GL_DIFFUSE, v);
	v[0] = -win->LightDirection[0]; v[1] = -win->LightDirection[1]; v[2] = -win->LightDirection[2]; v[3] = 0.0f;
	glLightfv(GL_LIGHT0, GL_POSITION, v);

	// Set material
	glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, win->MatAmbient);
	glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, win->MatDiffuse);

	// Rotate and draw shape
	glPushMatrix();
	glTranslatef(0.5f, -0.3f, 0.0f);
	if( win->AutoRotate )
	{
		float axis[3] = { 0, 1, 0 };
		float angle = (float)(GetTimeMs()-win->RotateTime)/1000.0f;
		float quat[4];
		SetQuaternionFromAxisAngle(axis, angle, quat);
		MultiplyQuaternions(win->RotateStart, quat, win->Rotation);
	}
	ConvertQuaternionToMatrix(win->Rotation, mat);
	glMultMatrixf(mat);
	glScalef(win->Zoom, win->Zoom, win->Zoom);
	glCallList(win->ObjectShape);
	glPopMatrix();

	// Draw tweak bars
	TwDraw();

	// Present frame buffer
	glutSwapBuffers();

	// Recall Display at next frame
	glutPostRedisplay();
}


// Callback function called by GLUT when sub-window size has changed
void ReshapeSubWindow(int width, int height)
{
	SubWindowData *win;

	win = GetCurrentSubWindowData();
	if (win == NULL) return;

	// Set OpenGL viewport and camera
	glViewport(0, 0, width, height);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(40, (double)width/height, 1, 10);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0,0,5, 0,0,0, 0,1,0);
	glTranslatef(0, 0.6f, -1);

	// Send the new window size to AntTweakBar
	TwSetCurrentWindow(win->WinID);
	TwWindowSize(width, height);
}


// Function called at exit
void Terminate(void)
{
	int i;
	for (i=0; i<2; i++) {
		glutSetWindow(g_SubWindowData[i].WinID);
		glDeleteLists(SHAPE_TEAPOT, NUM_SHAPES);
	}
	TwTerminate();
}


//	Callback function called when the 'AutoRotate' variable value of the tweak bar has changed
void TW_CALL SetAutoRotateCB(const void *value, void *clientData)
{
	SubWindowData *win;

	win = (SubWindowData *)clientData;
	win->AutoRotate = *(const int *)value; // copy value to win->AutoRotate

	if (win->AutoRotate != 0)
	{
		// init rotation
		win->RotateTime = GetTimeMs();
		win->RotateStart[0] = win->Rotation[0];
		win->RotateStart[1] = win->Rotation[1];
		win->RotateStart[2] = win->Rotation[2];
		win->RotateStart[3] = win->Rotation[3];
	}

	// make Rotation variable read-only or read-write
	TwSetCurrentWindow(win->WinID);
	TwSetParam(win->Bar, "ObjRotation", "readonly", TW_PARAM_INT32, 1, &win->AutoRotate);
}


//	Callback function called by the tweak bar to get the 'AutoRotate' value
void TW_CALL GetAutoRotateCB(void *value, void *clientData)
{
	SubWindowData *win;

	win = (SubWindowData *)clientData;
	*(int *)value = win->AutoRotate; // copy win->AutoRotate to value
}


// Mouse Button event callbacks
int MouseButtonCB(int glutButton, int glutState, int mouseX, int mouseY)
{
	TwSetCurrentWindow(glutGetWindow());
	return TwEventMouseButtonGLUT(glutButton,glutState,mouseX,mouseY);
}


// Mouse Motion event callbacks
int MouseMotionCB(int mouseX, int mouseY)
{
	TwSetCurrentWindow(glutGetWindow());
	return TwEventMouseMotionGLUT(mouseX,mouseY);
}


// Keyboard event callbacks
int KeyboardCB(unsigned char glutKey, int mouseX, int mouseY)
{
	TwSetCurrentWindow(glutGetWindow());
	return TwEventKeyboardGLUT(glutKey,mouseX,mouseY);
}


// Special key event callbacks
int SpecialKeyCB(int glutKey, int mouseX, int mouseY)
{
	TwSetCurrentWindow(glutGetWindow());
	return TwEventSpecialGLUT(glutKey,mouseX,mouseY);
}


// Setup new sub-window
void SetupSubWindow(int subWinIdx)
{
	float axis[] = { 0.7f, 0.7f, 0.0f }; // initial model rotation
	float angle = 0.8f;
	SubWindowData *win;

	win = &g_SubWindowData[subWinIdx];
	win->ObjectShape = (subWinIdx == 0) ? SHAPE_TEAPOT : SHAPE_TORUS;
	win->Zoom = 1;
	win->AutoRotate = (subWinIdx == 0);
	win->MatAmbient[0] = (subWinIdx == 1) ? 0.0f : 0.5f;; win->MatAmbient[1] = win->MatAmbient[2] = 0.2f; win->MatAmbient[3] = 1;
	win->MatDiffuse[0] = (subWinIdx == 1) ? 0.0f : 1.0f; win->MatDiffuse[1] = 1; win->MatDiffuse[2] = 0; win->MatDiffuse[3] = 1;
	win->LightMultiplier = 1;
	win->LightDirection[0] = win->LightDirection[1] = win->LightDirection[2] = -0.57735f;
	win->RotateTime = GetTimeMs();
	SetQuaternionFromAxisAngle(axis, angle, win->Rotation);
	SetQuaternionFromAxisAngle(axis, angle, win->RotateStart);

	glutSetWindow(win->WinID);
	// Set GLUT callbacks
	glutDisplayFunc(DisplaySubWindow);
	glutReshapeFunc(ReshapeSubWindow);
	// Set GLUT event callbacks
	// - Register mouse button events callback
	glutMouseFunc((GLUTmousebuttonfun)MouseButtonCB);
	// - Register mouse motion events callback
	glutMotionFunc((GLUTmousemotionfun)MouseMotionCB);
	// - Register mouse "passive" motion events (same as Motion)
	glutPassiveMotionFunc((GLUTmousemotionfun)MouseMotionCB);
	// - Register keyboard events callback
	glutKeyboardFunc((GLUTkeyboardfun)KeyboardCB);
	// - Register special key events callback
	glutSpecialFunc((GLUTspecialfun)SpecialKeyCB);
	// - Send 'glutGetModifers' function pointer to AntTweakBar;
	//	 required because the GLUT key event functions do not report key modifiers states.
	TwGLUTModifiersFunc(glutGetModifiers);

	// Create some 3D objects (stored in display lists)
	glNewList(SHAPE_TEAPOT, GL_COMPILE);
	glutSolidTeapot(1.0);
	glEndList();
	glNewList(SHAPE_TORUS, GL_COMPILE);
	glutSolidTorus(0.3, 1.0, 16, 32);
	glEndList();
	glNewList(SHAPE_CONE, GL_COMPILE);
	glutSolidCone(1.0, 1.5, 64, 4);
	glEndList();

	// Declare this window as current for AntTweakBar.
	// Here, this will create a new AntTweakBar context for this window,
	// which will be identified by the number WinID.
	TwSetCurrentWindow(win->WinID);

	// Create a tweak bar
	win->Bar = TwNewBar("TweakBar");
	TwDefine(" GLOBAL help='This example shows how to use AntTweakBar with multiple windows.' "); // Message added to the help bar.
	TwDefine(" TweakBar size='200 400' color='96 216 224' "); // change default tweak bar size and color

	// Add 'win->Zoom' to 'bar': this is a modifable (RW) variable of type TW_TYPE_FLOAT. Its key shortcuts are [z] and [Z].
	TwAddVarRW(win->Bar, "Zoom", TW_TYPE_FLOAT, &win->Zoom,
			   " min=0.01 max=2.5 step=0.01 keyIncr=z keyDecr=Z help='Scale the object (1=original size).' ");

	// Add 'win->Rotation' to 'bar': this is a variable of type TW_TYPE_QUAT4F which defines the object's orientation
	TwAddVarRW(win->Bar, "ObjRotation", TW_TYPE_QUAT4F, &win->Rotation,
			   " label='Object rotation' open help='Change the object orientation.' ");

	// Add callback to toggle auto-rotate mode (callback functions are defined above).
	TwAddVarCB(win->Bar, "AutoRotate", TW_TYPE_BOOL32, SetAutoRotateCB, GetAutoRotateCB, win,
			   " label='Auto-rotate' key=space help='Toggle auto-rotate mode.' ");

	// Add 'win->LightMultiplier' to 'bar': this is a variable of type TW_TYPE_FLOAT. Its key shortcuts are [+] and [-].
	TwAddVarRW(win->Bar, "Multiplier", TW_TYPE_FLOAT, &win->LightMultiplier,
			   " label='Light booster' min=0.1 max=4 step=0.02 keyIncr='+' keyDecr='-' help='Increase/decrease the light power.' ");

	// Add 'win->LightDirection' to 'bar': this is a variable of type TW_TYPE_DIR3F which defines the light direction
	TwAddVarRW(win->Bar, "LightDir", TW_TYPE_DIR3F, &win->LightDirection,
			   " label='Light direction' open help='Change the light direction.' ");

	// Add 'win->MatAmbient' to 'bar': this is a variable of type TW_TYPE_COLOR3F (3 floats color, alpha is ignored)
	// and is inserted into a group named 'Material'.
	TwAddVarRW(win->Bar, "Ambient", TW_TYPE_COLOR3F, &win->MatAmbient, " group='Material' ");

	// Add 'win->MatDiffuse' to 'bar': this is a variable of type TW_TYPE_COLOR3F (3 floats color, alpha is ignored)
	// and is inserted into group 'Material'.
	TwAddVarRW(win->Bar, "Diffuse", TW_TYPE_COLOR3F, &win->MatDiffuse, " group='Material' ");

	// Add the enum variable 'win->ObjectShape' to 'bar'
	// (before adding an enum variable, its enum type must be declared to AntTweakBar as follow)
	{
		// ShapeEV associates Shape enum values with labels that will be displayed instead of enum values
		TwEnumVal shapeEV[NUM_SHAPES] = { {SHAPE_TEAPOT, "Teapot"}, {SHAPE_TORUS, "Torus"}, {SHAPE_CONE, "Cone"} };
		// Create a type for the enum shapeEV
		TwType shapeType = TwDefineEnum("ShapeType", shapeEV, NUM_SHAPES);
		// add 'win->CurrentShape' to 'bar': this is a variable of type ShapeType. Its key shortcuts are [<] and [>].
		TwAddVarRW(win->Bar, "Shape", shapeType, &win->ObjectShape, " keyIncr='<' keyDecr='>' help='Change object shape.' ");
	}
}


// Main
int main(int argc, char *argv[])
{
	int mainWinID;

	// Initialize GLUT
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(960, 480);
	mainWinID = glutCreateWindow("AntTweakBar multi-window example");
	glutCreateMenu(NULL);
	glutDisplayFunc(DisplayMainWindow);
	glutReshapeFunc(ReshapeMainWindow);

	// Initialize AntTweakBar
	TwInit(TW_OPENGL, NULL);

	// Create two sub-windows
	g_SubWindowData[0].WinID = glutCreateSubWindow(mainWinID, 8, 8, 480, 464);
	SetupSubWindow(0);
	g_SubWindowData[1].WinID = glutCreateSubWindow(mainWinID, 488, 8, 464, 464);
	SetupSubWindow(1);

	atexit(Terminate);	// Called after glutMainLoop ends

	// Call the GLUT main loop
	glutMainLoop();

	return 0;
}

